Norovirus, often nicknamed the stomach “flu” or stomach bug, is a common but unwelcome visitor, especially during the colder months. Norovirus, which describes the inflammation of the stomach and intestines, brings unpleasant symptoms like nausea, vomiting and diarrhea. However, despite its nickname, norovirus is not related to the flu and cannot be prevented by the annual flu shot.
In the U.S., norovirus is the leading cause of stomach flu, with the Centers for Disease Control and Prevention (CDC) reporting 19 to 21 million cases each year. It also leads to an estimated 465,000 emergency room visits and 2.3 million doctor visits annually. Outbreaks are most common from November through April, but this season, the virus got a head start, beginning to spread in mid-October.
Data from the CDC suggests that cases of norovirus are on the rise and earlier than usual. In addition, wastewater samples from WastewaterSCAN show cases have been climbing steadily over the past three weeks, a reminder of how quickly norovirus can spread — just in time for the busy holiday season.
To make matters more challenging, a new strain of norovirus, GII.17, became the dominant player during the 2024-25 season. This strain caused 75 percent of outbreaks, a sharp increase from less than 10 percent just two years earlier, overtaking the previously common GII.4 strain. The CDC emphasizes the importance of monitoring new strains to better understand and manage outbreaks.
Norovirus is highly contagious and spreads rapidly through households, schools and public spaces. While most cases resolve on their own, it’s crucial to recognize the symptoms, understand how long they last and know when to seek medical care.
FAQs About the Norovirus Stomach Virus
What Causes Norovirus?
Norovirus is caused by a highly contagious virus that spreads through contaminated food, water, surfaces, or from direct contact with an infected person.
Even a tiny amount of viral particles—which are too small to see—can cause this type of infection. Norovirus can survive on surfaces for days and is resistant to many disinfectants, making it easy to spread in crowded places.
How Can You Tell If You Have Norovirus?
Norovirus symptoms usually come on quickly, often within 12 to 48 hours after exposure.
Common signs of norovirus include:
- Nausea
- Vomiting
- Diarrhea (often watery and frequent)
- Stomach cramps or pain
- Low-grade fever or chills
- Fatigue and body aches
Norovirus symptoms can range from mild to severe, but dehydration is one of the main concerns due to the rapid fluid loss caused by vomiting and diarrhea. Symptoms of dehydration include dry mouth, extreme thirst, dark urine and dizziness.
Does Everyone in a House Get Norovirus?
Norovirus is extremely contagious, making it likely that multiple members of a household will catch the virus. Most people with the virus will be contagious for at least two to three days.
The virus spreads through:
- Direct contact with an infected person
- Contaminated surfaces (like doorknobs or countertops)
- Consuming contaminated food or water
However, not everyone will necessarily get sick if they’re exposed to the virus, as immunity, hygiene habits and exposure levels can vary. Practicing good hygiene—like frequent handwashing and disinfecting commonly touched surfaces—can help reduce the spread.
How Long Are You Contagious With Norovirus?
People with norovirus are most contagious while they are actively experiencing symptoms, particularly vomiting and diarrhea. However, you can still spread the virus even after symptoms subside.
Here’s what you need to know about the likelihood of norovirus spreading:
- While symptoms are active: You are highly contagious.
- After symptoms have stopped: You can still spread the virus for up to two days (and in some cases, longer).
To help protect yourself against norovirus and prevent the virus from spreading to others:
- Avoid close contact with those who are sick.
- If you or a family member gets sick, stay home until at least 48 hours after symptoms stop to avoid spreading the virus.
- Don’t prepare food for others or share utensils if you’re sick.
- Wash your hands frequently for at least 20 seconds with soap and water. Alcohol-based hand sanitizers are less effective against norovirus than washing with soap.
How Do You Disinfect Your Home if Someone Has Norvorus?
Cleaning and disinfecting your home (or office or classroom) after norovirus exposure can help prevent others from getting sick. Other healthy habits, like regular hand washing and staying away from sick people, are also helpful.
Here’s how to kill germs that can cause norovirus to spread:
- Wear rubber or disposable gloves when cleaning, especially if there’s been vomit or feces.
- Clean areas exposed to diarrhea or vomit with a bleach solution (5 to 25 tablespoons per gallon of water) or an EPA-approved disinfectant for norovirus. Let it sit for at least 5 minutes. Then wash the area again with soap and hot water. Use paper towels and discard them in a plastic trash bag that has been sealed.
- Remove contaminated clothes or linens immediately. Wash them with detergent and hot water on the longest cycle, then machine dry at the highest heat.
- Take out the trash and wash your hands thoroughly with soap and water.
How Long Does it Take to Get Over Norovirus?
For most people, norovirus symptoms last one to three days. In some cases, lingering fatigue or mild gastrointestinal discomfort can last a few more days as your body fully recovers.
Recovery time may be longer for:
- Young children and infants
- Elderly individuals
- People with compromised immune systems
If you’re caring for someone with norovirus, it’s important to monitor for signs of dehydration (like extreme thirst and dizziness), as they may need more fluids or medical attention.
What Remedies Help With Norovirus Symptoms?
While there’s no specific treatment for norovirus (including antibiotics, which won’t help resolve a virus), supportive care can help manage symptoms and prevent complications.
Here are some remedies to help you feel better:
- Hydration: Drink small sips of water, electrolyte drinks (such as Gatorade or similar drinks, and Pedialyte or similar fluids your pediatrician recommends) or broth frequently to prevent dehydration. If nausea or vomiting makes it difficult to keep fluids down, try sucking on ice chips or small amounts of a rehydration solution.
- Rest: Allow your body to recover by getting plenty of sleep and avoiding strenuous activity.
- Bland foods: Once you can keep food down, stick to gentle options like bananas, rice, applesauce, toast (the BRAT diet), or plain crackers.
- Avoid irritants: Stay away from caffeine, alcohol, spicy foods and dairy until your stomach settles.
When Should I Go to a Doctor for Norovirus?
Most cases of stomach flu resolve on their own without the need for medical treatment.
However, you should see a doctor if you experience:
- Persistent vomiting lasting more than 24 hours
- Inability to keep fluids down
- Signs of severe dehydration (dizziness, confusion, low urine output or rapid heartbeat)
- Blood in your stool or vomit
- A high fever (above 102°F for adults and 100.4°F in children) that lasts more than two days
In infants, elderly individuals, or those with underlying health conditions, medical evaluation is recommended sooner to prevent complications.
If you or a loved one are experiencing severe norovirus symptoms such as dehydration, persistent vomiting, or difficulty keeping fluids down, the experts at Stony Brook Medicine are here to help. Our team provides compassionate care and comprehensive treatment to support your recovery and prevent complications. Don’t hesitate to reach out for personalized medical guidance and the care you and your family need to feel better.
This article has been updated from its original publish date of January 27, 2025 with the latest facts and figures on norovirus.
